Astragalus injection inhibits c-Jun N terminal kinase mRNA expression following oxygen-glucose deprivation and reintroduction in rat hippocampal neurons

BACKGROUND： In studies concerning cell injury induced by cerebral ischemia-reperfusion, current experiments have primarily focused on altered protein levels. In addition, the apoptotic proteins Bax and Bcl-2 have been thoroughly studied with regard to initiating neuronal apoptosis. OBJECTIVE： To establish an in vitro model of oxygen-glucose deprivation and reintroduction in the rat hippocampus to simulate cerebral ischemia-reperfusion injury; to observe c-Jun N-terminal kinase 3 （JNK3） mRNA expression in hippocampal neurons following Astragalus injection; and thus to determine changes in the signaling and downstream pathways of neuronal apoptosis at the cellular and molecular level. DESIGN, TIME AND SETTING： A randomized, controlled, cellular and molecular experiment was performed at the Department of Central Laboratory, Chengde Medical College from February to June 2008. MATERIALS： Astragalus injection, the main ingredient of astragaloside, was purchased from Chengdu Di＇ao Jiuhong Pharmaceutical Manufactory, China. JNK3 mRNA probe and in situ hybridization kit were purchased from Tianjin Haoyang Biological Technology, China, and JNK3 RT-PCR primers were designed by Shanghai Bio-engineering, China. METHODS： Primary cultures of hippocampal neurons derived from Sprague Dawley rats, aged 1 2 days, were established. After 8 days, the hippocampal neurons were assigned to the following interventions： model group, Astragalus group, and vehicle control group, cells were subjected to oxygen-glucose reintroduction after oxygen-glucose deprivation for 30 minutes in sugar-free Earle＇s solution and a hypoxia device, which contained high-purity nitrogen. The normal control group was subjected to primary culture techniques and was not treated using above-mentioned interventions. In addition, the Astragalus and vehicle control groups were treated with Astragalus injection （0.5 g/L raw drug） or sterile, deionized water at 2 hours prior to oxygen-glucose deprivation, respectively. MAIN OUTCOME MEASURES： JNK3 mRNA expression was measured by in situ hybridization and RT-PCR at 0, 0.5, 2, 6, 24, 72, and 120 hours after oxygen-glucose reintroduction. RESULTS： Hippocampal neuronal morphology was normal in the normal control group. Hippocampal neurons exhibited apparent apoptosis-like pathological changes in the model, as well as the vehicle control, groups. The apoptosis-like pathological changes in the hippocampal neurons were less in the Astragalus group. Results from in situ hybridization and RT-PCR showed that JNK3 mRNA expression significantly increased in hippocampal neurons from model group, as well as the vehicle control group, compared with the normal control group （P 〈 0.05）. In addition, JNK3 mRNA expression significantly decreased in hippocampal neurons of the Astragalus group, compared with the model group and vehicle control group （P 〈 0.05）. CONCLUSION： Astragalus injection inhibited apoptosis-related JNK3 mRNA expression following oxygen-glucose deprivation and reintroduction, and accordingly played a role in inhibiting hippocampal neuronal apoptosis.

Effect of intracranial hypertension on cerebral hemorrhage induced autonomic nerve imbalance

BACKGROUND： Cerebral hemorrhage can cause the imbalance of nerve function, whereas its mechanism and main impact factors are still not quite clear. OBJECTIVE： To explore the rules about the changes of intracranial pressure in brainstem hemorrhage and internal capsule hemorrhage, and analyze the role of intracranial hypertension in the changes of nerve function caused by cerebral hemorrhage. DESIGN： A self-controlled trial. SETTING： Department of Physiology, Tianjin Medical University. MATERIALS： Sixty-five healthy male Japanese white rabbits with long ears （1.5-1.8 kg） were supplied and fed by the Department of Animal Experiment of Tianjin Medical University. The RM6240B biological signal collecting and processing system was used. METHODS： The experiments were conducted in the Department of Physiology, Tianjin Medical University from August 2001 to May 2006. ① The rabbits were anesthetized, then fixed onto the brain stereotaxic apparatus, and afterwards fenestration on skull and intubation to lateral ventricle were performed.The dynamic changes of intracranial pressure were monitored continuously. Rabbits were infused with autologous arterial blood （0.3 mL） into midbrain corpora quadrigemina inferior colliculus to induce model of acute brainstem hemorrhage; models of internal capsule hemorrhage were established by infusing autologous arterial blood into internal capsule. ② The dynamic intracranial pressures under the above conditions were recorded continuously with the RM6240B biological signal collecting and processing system. ③ An animal model of persistent intracranial hypertension was established by infusion of physiologic saline into lateral ventricle. ④ The changes of the intensity of autonomic nerve discharge were analyzed, using the biological signal collecting and processing system before and after hemorrhage and under persistent intracranial hypertension.⑤ Ten animal models of internal capsule hemorrhage and 10 of bminstem hemorrhage were selected respectively, then gross pathological samples were cut open, and the accuracy of hemorrhage models was affirmed. Histological sections in hemorrhage point and around this point were prepared for with hernatoxylin and eosin staining, and the pathological changes were observed under light microscope. MAIN OUTCOME MEASURES： ① Changes of intracranial pressures before and after internal capsule hemorrhage and brainstem hemorrhage; ②Changes of the discharge intensity of cervical vagus nerve trunk in animal models of internal capsule hemorrhage, brainstem hemorrhage and persistent intracranial hypertension without hemorrhage; ③ Accuracy of location of internal capsule hemorrhage and brainstem hemorrhage confirmed by gross pathological samples and sections. RESULTS： Totally 65 rabbits were involved in the analysis of results. ① Dynamic state of intracranial pressure： Intracranial pressure increased obviously at 45 minutes after internal capsule hemorrhage and brainstem hemorrhage, the intracranial pressures were （1.31 ±0.30）, （1.82±0.45） kPa, which were obviously higher than those before hemorrhage [（1,04±0.18）, （1.05±0.19） kPa, P 〈 0.01]. ② Discharge of vagus nerve： Under intracranial hypertension, the discharge of cervical vagus nerve trunk was enhanced, and the discharge intensity of vagus nerve trunk was significantly different before and after persistent intracranial hypertension [（364.28±78.55）, （1252.19±151.75）μ V·s, P 〈 0.01]. The discharges of cervical vagus nerve trunk were significantly enhanced after internal capsule hemorrhage and brainstem hemorrhage （P 〈 0.01）. ③ Validation of hemorrhage sites： The hemorrhage sites were internal capsule and brainstem on histopathological sections. CONCLUSION： Intracranial pressure may play an important role in the pathophysiological process of vagus nerve imbalance caused by cerebral hemorrhage.

Impact of meteorological conditions on a nine-day particulate matter pollution event observed in December 2013,Shanghai,China

A severe particulate matter pollution event occurred in Shanghai from 1 to 9 December 2013. The mean hourly mass concentrations of PM2.5 and PM10 were 211.9 and 249.0 μg/m3, respectively. Reanalysis data, in situ, and remote-sensing measurements were used to examine the impacts of meteorological conditions on this event. It was found that the synoptic pattern of weak pressure, the reduced planetary boundary layer height, and the passage of two cold fronts were key factors causing the event. Four stages were identified during this event based on the evolution of its PM2.5 levels and weather conditions. The highest concentration of PM2.5 （602 μg/m3） was observed in stage 3. High PM2.5 concentrations were closely associated with a low local ventilation index, with an average of 505 m2/s, as well as with the influx of pollutants from upstream, transported by the cold fronts.